"I was fatigued and mentally worn down, and I didn't know how hard AFL footy was," he said.
"During the week I used to think about footy, footy, footy, which is why I was fried by round nine and I ended up heading home for a break."
Finlayson played five more games in 2018 but never recaptured his best and failed to play in any of the club's finals. In 2019, however, he's been a revelation, kicking 37 goals from 19 games playing as a forward.
The athletic goalkicker credited his work with GWS sports psychologist Darren Everett as a major reason behind his form this year.
"I probably see Darren twice a week and he's been huge in helping me deal with the pressures of being a full-time footballer," he said.
"Without Darren I'd probably be struggling like I was this time last year. We've seen some of the best players in the comp taking some time off this year so it can affect anyone.
"Everyone thinks it’s a free ride playing in the AFL but it's pretty challenging sometimes."